<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .round1 {
            width: 500px;
            height: 500px;
            border: 10px solid black;
            background-color: blue;
            display: flex;
            justify-content: center;
            align-items: center;
            border-radius: 50%;
        }

        .round2 {
            width: 400px;
            height: 400px;
            border: 10px solid #000;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .round3 {
            width: 300px;
            height: 300px;
            border: 10px solid #000;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .round4 {
            width: 200px;
            height: 200px;
            border: 10px solid #000;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .round5 {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background-color: red;
            margin: 20px;
            

        }
    </style>
</head>

<body>

    <div class="round1">
        <div class="round2">
            <div class="round3">
                <div class="round4">
                    <div class="round5"></div>
                </div>
            </div>
        </div>
    </div>
</body>

</html>